Dear Mr. Kunjroy,
If your establishment is covered under the Factories Act, 1948, please follow Chapter VIII Section 78 and 79.
Section 79 reads as under :
"Annual leave with wages- Every worker who has worked for a period of 240 days or more in a factory during a calendar year shall be allowed during the subsequent calendar year, leave with wages for a number of days calculated at the rate of --
(i) if an adult, one day for every twenty days of work performed by him during the previous calendar year; ............."
Also, you can go through the explanations given in the Factories Act, 1948.
For your guidance, enclosed please find herewith a draft leave rules and procedure to avail the leave so that you can prepare leave rules for your establishment.
Regards
T M Rao